First thunderstorm: May 13Last thunderstorm: September 27Length of thunderstorm season: 138 daysLength of off-season: 199 days [Oct 26, 2008 to May 12, 2009]Extreme daily thunderstorm duration: 335 minutes on August 14 (5 hours 35 minutes)Severe thunderstorms: August 14 (due to the hail)Days with hail: July 9 (pea and dime) and August 14 (nickel)... all associated with thunderstorms